How does the size of your room affect the size monitor you get?

[Big 3rd]

I hear many ask others about the size of their control room in regards to selecting monitors. I want to know from you, what would the outcome be if you have monitors that are "too much" for your room vs. having something thats just right? How can you tell the difference?

I ask this because I wanted to upgrade my monitors from hr824s to something like the S-3a's, bm15a's, pml's, you know something that has accuracy and can really bang when I need it to. But, many say the room size should be your guide towards the size of the monitor that you're going to purchase. What does it sound like to have monitors that are too much?

[Fletcher]

It doesn't.

You're sitting 3-4 feet away from the speakers, they're pointed at your head... the only size issue is whether or not you can hear all the elements of the speaker [in other words is the tweeter aimed 3 feet over your head or not]. There are 'full range' monitors and less than full range monitors... the bullshit that "oh that's too much speaker for the room" is absolute rubbish. If all the components of the monitor are in line with the listening position, then the size is fine.

The room will play some role in your monitoring but only from the aspect of the modal response of the room [like whether some frequencies are reinforced by the room in the bass or whether some frequencies are killed by the room in the bass, or both] and what you have for upper frequency reflections which will do a similar thing as the bass modal stuff except that the anomolies will change from place to place in front of the console.

Want some fun? Here's an interesting example... take a 1kHz test tone and run it through the monitors... now move your head from side to side... freaky ain't it.

[warhead]

I actually have a pretty strange room, it's a loft over my garage. It's 500 sq feet and makes for a good one room setup but it makes for some limited choices of where to sit because of the slant ceiling deal.

I used to monitor in the center of the room with the speakers perfectly centered and 3 feet out from the walls etc. After a while I started realizing that ideally it'd be better for me to use this as the tracking and drum area and I figured what the hell, I'll try a corner.

And the corner's fine. I've used bass absorption in a different manner, and I use a free standing cubicle style wall to even things out at the listening position, but it's been fine. You learn the space you're in and use absorbing materials where needed. I use the HR824's also and the low end EQ on board has been handy. My speakers are also now less than one foot from the wall but again I've made it work fine. The only thing that bugs me is my left speaker side (the one in the "real" corner) is 1dB hotter at louder volumes but it's mostly just a slight difference in low end (it's building up a bit more there).

If there were perfect solutions to this stuff that'd be great. The room comes more into play the louder you monitor but again, learn your space and optimize it.

War

[weedmaker]

In small, untreated, masonry room you should avoid speakers that have a considerable energy below certain lo-freq point (exact point depends on room and abovementioned modal distribution), otherwise you could end up with muddy bottom end. Better than avoiding bottom extended speakers is to TREAT the room!

As far as physical size of speakers is concerned, you should try to follow manufacturer's specification: i.e. you shouldn’t use main monitor in nearfield configuration. The only reason for that is that physically huge monitors are sound coherent only after some distance and have minimum recommended listening distance of typically between 1.5-2.5m (5-9 feet).

Hope it helps.

[Bob Olhsson]

A great deal depends on a room's construction. Small, and even medium sized truly "soundproof" rooms are very hard to deal with but rooms having an ordinary level of low frequency leakage are effectively huge.

The idea of a room being "too small for a full range speaker" is bunk left over from 1960s bookshelf speaker marketing blurbs. So is the idea that only one speaker is needed to reproduce ultra low frequencies in stereo. It's been amazing how often people who rail on about the mysticism of wire will turn right around and parrot the hi fi hype they want to believe.

[weedmaker]

Originally Posted by Bob Olhsson

So is the idea that only one speaker is needed to reproduce ultra low frequencies in stereo.

This is very, very true!!! I wonder why people believe that you only need one sub for stereo!? One sub -> MONO bellow your crossover point!!

If someone is skeptic, try using 50 hz sine wave (if your "satellite" speakers goes this low - 60Hz will do fine otherwise) and pan it around L-R. Myth says that you don't hear spatial difference bellow 200Hz.

Ha-ha, myth busted! You do need TWO subwoofers if you work in stereo or better yet use full range speakers!

Cheers

[seriousfun]

Originally Posted by weedmaker

... I wonder why people believe that you only need one sub for stereo!? ...
...

Science.

Originally Posted by weedmaker

...You do need TWO subwoofers if you work in stereo or better yet use full range speakers!
...

Fundamental tones (sine waves, no harmonic content) below 100 Hz are not localizeable - for example, if a speaker is playing a 40 Hz tone and you move the speaker around the listener in a room with no modal frequency-response dips or peaks, the listener can not perceive where the speaker is located. Fact.

If you pan a 40 Hz fundamental L-R (or even worse, L- Rs, C-Ls, etc.), and you hear the pan, you are hearing the modal response of the room, feeling the air move your pants leg, hearing speaker/floor/wall rattles, etc., not localizing a fundamental.

The problem, of course, is that we rarely if ever monitor pure fundamental tones - musical content usually has harmonic content, and the harmonic content cues our ears as to where the speakers are located. Subtle differences in modal response are difficult to measure (or at least not commonly measured properly), but simple and obvious to hear.

Full-range monitoring has to mean that your speaker system/room can reproduce everything you can acquire and everything you can deliver, and current technology is at least 20 Hz to 20k hz, of course. Whether you do this with true full-range monitors or limited-range monitors with properly integrated subwoofer(s) is your choice - they both work. Most rooms do not support using five full-range monitors for a 5.1 system (room modal response makes the speakers deliver five different frequency response curves to the listener) and true full-range speakers are large, expensive, and difficult to place. Small main/subwoofer systems need lots of work to implement properly, but they can be more affordable and easier to position.

If you choose to extend the frequency response of your mains with a subwoofer, you can place the subwoofer where it will deliver flat response to the engineer, something you can't do with full-range speakers. This becomes even more of an advantage with more-than-2-channel systems - all six channels of a 5.1 system can have identical flat frequency response if the subwoofer is positioned and integrated properly.

Once this is done, you can choose whether to use more than one subwoofer is your headroom needs are exceeded using just one; sometimes the second subwoofer is placed to couple with the first for more output/headroom, and sometimes (much more rarely than imagined) in a complementary place in the room to provide even flatter frequency response. There is no need to add subwoofers running from extra channels - the localizable content is played by the main speakers, not the subwoofer. You can prove this by panning a bass instrument with rich harmonic content, string bass for example, around the room in a stereo (2-or-more-channel) system blindfolded - the proven psychoacoustic effect is that the whole instrument, not just the harmonic content, sounds as if it is being panned around the room. If this does not happen, there are problems with subwoofer placement/design/implementation.

[Ethan Winer]

Folks,

> many say the room size should be your guide towards the size of the monitor <

I'll add my agreement to all the posters who said speaker size is unrelated to room size. As long as you can physically fit it in the room, and as Fletcher said the tweeters aren't three feet over your head, you'll be fine.

Also, Doug nailed it with this comment:

> If you pan a 40 Hz fundamental ... and you hear the pan, you are hearing the modal response of the room, feeling the air move your pants leg, hearing speaker/floor/wall rattles, etc., not localizing a fundamental. <

Not only do bass instruments have harmonic content, most speakers add their own distortion at very low frequencies. I can localize bass instruments very well in my "acoustically correct" home theater, yet I have a single subwoofer way up in the front left corner of the room. The deepest stuff comes from the sub, but the "speaking range" of bass instruments is much higher than most crossover frequencies. So discounting those cheap home-theater-in-a-box setups with tiny satellites crossed over at 300 Hz, having only one sub is not a problem in most rooms.

--Ethan

[lucey]

Originally Posted by Fletcher

The room will play some role in your monitoring but only from the aspect of the modal response of the room [like whether some frequencies are reinforced by the room in the bass or whether some frequencies are killed by the room in the bass, or both] and what you have for upper frequency reflections which will do a similar thing as the bass modal stuff except that the anomolies will change from place to place in front of the console.

This is understated. (Fletcher sells monitors, not treatments.) There are modal responses, first reflections, front wall reflections, rear wall reflections, and the speaker throw differences (short wall throw vs. long wall throw).

As I hear it the room is a huge factor and becomes an even larger factor with monitors that are more interactive. You named the BM15 and S3A and they're good examples of opposites in this respect.

The S3As are great for smaller rooms as they have tight, low bass and are very directional in the tweeter. This means less treatments are needed both for the bass and the first reflections and it means more consistency from room to room. However, this tight low end is not ass-kicking for clients and as it's low end is as much from the port as the small sub driver, there are compromises there ... meanwhile the narrow tweeter dispersion and ribbon design are not common to playback systems and it does not interact with the room. So there is bad with the good.

Then there is the BM 15 option with an innate big low end and a more traditional tweeter material, yet the distortions of that design are higher, including the crossover is in the crucial midrange, and the usual limitations of 2 way systems ... the big bottom means more bass trapping and the wider tweeter means more first reflection treatments . All this makes it more work for many rooms that the S3A. And in the end, they're so differerent in a vacuum anyway.

A monitor needs to work with not only the user but the room and this takes some doing.

In general I prefer 3 ways (insert sex joke here) with a sub driver that is larger and relies less on the porting.

[weedmaker]

Originally Posted by seriousfun

Fundamental tones (sine waves, no harmonic content) below 100 Hz are not localizeable - for example, if a speaker is playing a 40 Hz tone and you move the speaker around the listener in a room with no modal frequency-response dips or peaks, the listener can not perceive where the speaker is located. Fact.

Only theoretically true, in anechoic room. In all practical situations, i.e. rooms with modal response and real world speakers, you'll hear 40Hz pan.

You can ALWAYS hear pure sine 40HZ tone pan in EVERY room I ever worked or listened in and that's a FACT !

If I can localize "pure sine" 40 Hz coming from, let's say left speaker, I bet that the end listener would hear the same, except if he/she is listening in anechoic chamber and on speakers WHITHOUT harmonic distortion (btw, harmonic distortion below 50 Hz in most high-end speakers is known to reach something like 10% or even much more very easily!).

Originally Posted by seriousfun

...
If you choose to extend the frequency response of your mains with a subwoofer, you can place the subwoofer where it will deliver flat response to the engineer, something you can't do with full-range speakers.
...

We are in high-end forum here. And I'll talk about ordinary stereo LR.

Properly (read expensive) designed control room with full range speakers (Genelecs 1034,1035,1039,1036; ADAM S5A,S6A; Dynaudio M3A, M4;etc..) are the BEST way to attempt flat response below 30Hz. One sub for EACH speaker is possible solution as well!

The other way, one sub + 2 mains is definetely compromise imaging wise with any current cone design in non-anechoic room if you crossover upwards of, lets say, 50 HZ (not to mention impulse response distortion caused by time missaligment between mains and sub!).

Only exception would be crossing over below 30Hz which is pointless IMHO, because you would already have “full range” monitors and need to do full room optimization for them anyway!

Of course, when the cost is issue, the 1 sub + 2 nearfield satellites are more than workable solution! But that’s another story….



Regards

[Ziggy!!]

apparently a 7Hz wave will make you wet your pants...

[seriousfun]

Originally Posted by weedmaker

Only theoretically true, in anechoic room. In all practical situations, i.e. rooms with modal response and real world speakers, you'll hear 40Hz pan.

...

Agreed, with a complex musical waveform - not agreed, with a 40 Hz sine wave.

Originally Posted by weedmaker

...

If I can localize "pure sine" 40 Hz coming from, let's say left speaker, I bet that the end listener would hear the same, except if he/she is listening in anechoic chamber and on speakers WHITHOUT harmonic distortion (btw, harmonic distortion below 50 Hz in most high-end speakers is known to reach something like 10% or even much more very easily!).


...

From my experience, reproducing information below 100 Hz is much better done with a dedicated bass monitor - a subwoofer. It has to be well designed, well matched with the mains, have tons of headroom, be well integrated with the mains, etc. A good Push-Pull, servo, or other system can reduce distortion, and works well in the limited frequency range of a subwoofer.

Originally Posted by weedmaker

...

Properly (read expensive) designed control room with full range speakers (Genelecs 1034,1035,1039,1036; ADAM S5A,S6A; Dynaudio M3A, M4;etc..) are the BEST way to attempt flat response below 30Hz. One sub for EACH speaker is possible solution as well!

...

IMO none of these are full-range - they are all (and there are some great speakers on the list...and of course great, translatable mixes get done daily on those speakers...) limited-range. Many cheaper home systems have an octave of low-end response that many professional monitoring systems do not, and I think this is self-defeating and has to change.

Originally Posted by weedmaker

...

The other way, one sub + 2 mains is definetely compromise imaging wise with any current cone design in non-anechoic room if you crossover upwards of, lets say, 50 HZ (not to mention impulse response distortion caused by time missaligment between mains and sub!).

But letting main speakers run below 80 Hz nearly always guarantees that they will run into modal response problems - IMO better to deliver flat extended bass response from a subwoofer.

Originally Posted by weedmaker

...

Only exception would be crossing over below 30Hz which is pointless IMHO, because you would already have “full range” monitors and need to do full room optimization for them anyway!

Actually, I have integrated a few subwoofers at nearly 25 Hz, on nearly full-range speakers. The subwoofers (mono multiples) have delivered stunning, deep, clean, dynamic bass. The end-result was a much more spacious sound than with supposedly stereo stuff coming from the main speakers. Headroom in the bass can fix a multitude of ills!

[weedmaker]

Hi Doug,

Fundamental 40Hz wave is, at least at the moment, only theoretical concept. There is no such thing in real world!

You can NEVER reproduce “pure” 40Hz sine wave with today woofer technology because of harmonic distortion issue, so we are talking about COMPLEX signal with a LOT of 2nd and 3rd order harmonics added although you input the pure, digitally generated sine into the system!

As I said, 10% acoustic THD is average figure for low-frequency woofer in enclosure for, let's say, 90dB SPL. The only reason why we are not complaining is that we actually never heard anything better so far . Anyone asked why manufacturers don't publish acoustic THD figures for less than 100Hz? .

You could mess with feedback with microphone and sofisticated electronics in front of the cone (Did Meyersound do something like that with x-10?) to try to minimize harmonic distortion but you will always end up hearing the distortion! Even they don't publish figures for acoustic THD!

So if we have 80 +160 + 320Hz etc... harmonics added to our 40Hz signal you can clearly localize it across LR or if you move your sub around EVEN in perfect room(which, btw, doesn't exist )! You should be able to hear 2nd order harmonic distortion greater than 1%; 3% being clearly audible; odd harmonics are even worse!!)

I confirmed this theory many times over with real world speakers, with standard 50Hz sine test signal! Everyone is encouraged to do the same (it's very simple test) and make his own judgment on this matter!

I fully agree with crossing over below 30Hz but ONLY AFTER optimizing room for mains (they're near full-range in this case so all usual modal problems influence them!). Maybe I didn' express myself clearly in the previous post (not a native English speaker )

IMHO, YMMV, etc...

Regards!

[Anderson]

Worked in a studio with PMCs and 2 subs, all I got was more phase cancellation (comb filtering etc)... so thanks, but no thanks. It's my only experience with such a setup, and yes, the CR had good professionnaly designed acoustics. (165/d-d' equation for those working in acoustics... ) One sub with low crossover is the way to go.

I think that in a way, if you have a small room, you should try to work with nearfields since using those will allow less room interference (SE closer to the speaker > direct sound). Using Midfields will let the room work more on your sound, since you will have to sit further away... in the reverberated field. As mentioned in this thread before, speakers directivity is important as well.

IMO 3 way speakers are working only from 2.5/3m. Before is just you listening to the mids and the lows.

Cheers

[weedmaker]

Originally Posted by Anderson

Worked in a studio with PMCs and 2 subs, all I got was more phase cancellation (comb filtering etc)... so thanks, but no thanks.

If you've heard phase cancellation than that room was not properly designed and/or speaker setup is wrong, simple as that . There are probably hundred of possible reasons why...

Cheers!

[Anderson]

Originally Posted by weedmaker

So if we have 80 +160 + 320Hz etc... harmonics added to our 40Hz signal you can clearly localize it across LR or if you move your sub around EVEN in perfect room(which, btw, doesn't exist )! You should be able to hear 2nd order harmonic distortion greater than 1%; 3% being clearly audible; odd harmonics are even worse!!)

I confirmed this theory many times over with real world speakers, with standard 50Hz sine test signal! Everyone is encouraged to do the same (it's very simple test) and make his own judgment on this matter!

One more thing: harmonics, in real life conditions (i.e. not pure sines) are present in the instrument/recorded material anyway. You will then localise the sounds' source in the stereo field thanks to the timing of I]those[/I] harmonics when they reach your ears.

In normal conditions those harmonics will be reproduced by the monitors. The sub may mechanically produce harmonics of its own, but since those speakers cut off quite fast, it does not interfere too much with the monitors. The sub generated harmonics may not have the same content than the instrument generated harmonics, but my guess is that it has a negligible impact, on a limited freq spectrum.

A bass tone will see it's fundamental reproduced by the sub (which the brain will be unable to locate, FACT) and the harmonics will be reproduced by the monitors, giving the brain infos regarding the localisation of the source.

What you hear when you pan your 50Hz sine with your 2 subs is your room + L/R spl & timing difference in the mechanically generated harmonics... Nothing very interesting IMHO

Cheers

[weedmaker]

Originally Posted by Anderson

...
What you hear when you pan your 50Hz sine with your 2 subs is your room + L/R spl & timing difference in the mechanically generated harmonics... Nothing very interesting IMHO

You hear PAN, i.e. clearly localized sound, btw stereo subs are not important for this to hear, two ordinary near full-range speakers without subs will do! Try it on your speakers with your sub turned off

Cheers

[weedmaker]

And try to move single full-range speaker around the anechoic chamber , or outdoors (fair compromise) with the same 50Hz signal applied. You should localize it because of added 2nd and 3rd harmonics!

[Anderson]

Originally Posted by weedmaker

If you've heard phase cancellation than that room was not properly designed and/or speaker setup is wrong, simple as that . There are probably hundred of possible reasons why...

Cheers!

I'm afraid it's not as simple as that! Ethan speaking a better english than I do may be of some help here, but I'm going to try to explain myself as clearly as possible!

Imagine you are sitting in your CR, and listening to a CD in the sweet spot. Now if you move your head 30 cm on the right, the distance between the left speaker and your head and the right speaker and your head, is not the same anymore. This fact alone is creating comb filtering in the way you hear the sound. There is a very simple equation to that phenomenon which is -as I mentioned- 165/d-d'. d-d' being the difference of distance in meters, so here for ex, 1.2-.9=30 cm. So you will have a first full phase cancellation at 550Hz + all harmonics. Keep in mind you loose a lot at 225Hz etc.. as well.

Now apply this to your 2 subs theory. Subs will emit sound in an omnidirectionnal way, thus all the walls will reflect the acoustic waves up to a certain extent. If you have one sub, the phenomenon can already be problematic, e.g. with a rear wall reflection that creates comb filters at specific low frequencies, blablabla. Now add a second sub, and let's say they are placed 2m appart in a classic CR design (Hexagon-ish style). Especially with mono material that will be played at equal SPL by the two subs, you clearly create more comb filtering since thanks to the rooms' wall interferences, that difference of distance will now add more phase related problems at specific pressure points, e.g. full cancelation @82,5Hz and 55Hz, that would not happen with a 1 sub system. So 2 subs do more harm than good, in theory... and most pbly in reality!

Hope that was clear... at least I understand myself

Cheers!

[weedmaker]

I see your point, and its a valid one for MONO material.

What's the point to monitor summed stereo low-frequency content if you're targeting stereo consumer Hi-Fi speakers in ordinary living room (and they go down below 30Hz nowadays)? Why don’t we monitor on single mono speaker all the time, then? That way we will get rid off any comb filtering etc... (btw, for reality check try to pan 1kHz sine and your head around, like Fletcher said )

Now you can say, and that's something we all learn/hear in magazines/books/schools/internet/etc, "You can't localize sound below 200Hz so crossover to mono sub at that freq!"

Although theoretically wrong, low-freq stereo content is CLEARLY audible with current technology of cone manufacturing.

So what happens if I want to use stereo (chorused) version of low B bass string (31 or so Hz fundamental)? I want to exploit non-perfect modern domestic Hi-Fi speakers in real rooms and get VERY wide low-freq field (we can use this technique nowadays not worrying about vinyl ). If I use mono sub and crossover at 80Hz which is very common crossover point, all of the sudden effect is LOST! It sounds VERY DIFFERENT on 2.0 and 2.1 system!!

BTW, Bruce Swedien is known to use XY omnis very often, which is something you shouldn't do according to microphone theory! The man is only exploiting imperfection in mike design!

Regards

[Anderson]

Originally Posted by weedmaker

What's the point to monitor summed stereo low-frequency content if you're targeting stereo consumer Hi-Fi speakers in ordinary living room (and they go down below 30Hz nowadays)? Why don’t we monitor on single mono speaker all the time, then? That way we will get rid off any comb filtering etc... (btw, for reality check try to pan 1kHz around )

Hehe!

As I said before, what makes you believe you can locate your low freq material is:

1. The mechanical harmonics that your speaker cone is generating (that have little or no relation to the harmonic content of the recorded material. If you play a 50Hz sine you will get those harmonics, if you play a 50Hz basse tone, you will get those +maybe the ones from the bass up to the speakers capacity, maybe 800Hz MAX and with very low SPL. But then again, those will be heard much louder from your main monitors, thus giving accurate stereo location.

2. The fact that you know that it is coming from a certain point influences you. There was a famous experiment about this phenomenon, with people sitting in front of a computer screen with heaphones. LF tones were played in the headphones, while a white square was displayed either L, R or C on the screen. Guess what? Although the LF was full mono, if the square was L of the screen people said the LF tone came from the left, etc same with right. It's your brain that fools you!

The point in monitoring low freq. in mono is that you have more accuracy regarding phase etc. Comb filtering with mid/high freq will affect the colour of the music but it won't be as bad as comb in the LF region: that's a killer. Been in an fully anechoic room btw, and that's freaky. Got kind of seasick . You really loose your references... weird.

Stereo starts working for us only from certain freq (>120Hz) and up, then doesn't work so good anymore (>1.5kHz), wether you like it or not, that's a fact. Depends on your physical constitution, but it's gonna be more or less the same for everyone!

But if you like to work with two subs, go ahead . What matters in the end is that you work in conditions you think will help you provide your best engineering. (Though I will not believe someone can actually locate a 40Hz sub. Maybe elephants...)

Me back to work... Cheers!

[weedmaker]

I'm somewhat big man; 1,95m and 135 kg so I guess I am qualified as elephant !!!

[Ethan Winer]

Anderson,

> Ethan speaking a better english than I do <

Your English is fine, but I'll point out something you may be missing:

> if you move your head ... is creating comb filtering <

Yes. But at low frequencies the wavelengths are long enough that two subs might still improve the overall response at the listening position. At least this is what I understand from people who I trust that have set up rooms with two subs. Me, I have one very loud sub and a ton of bass trapping, so I'm happy. And this is the real issue.

No matter how you arrange speakers in a room you'll have peaks and severe nulls all over the place. I once compared speaker placement versus bass traps. I didn't try every possible speaker placement, but I did methodically move them in 6 inch increments and measure the LF response at each place. As expected, the best placement had a flatter LF response than the worst placement. But with bass traps in the room the worst placement was infinitely better than the best placement with no traps.

--Ethan

[Ethan Winer]

Anderson,

> This fact alone is creating comb filtering in the way you hear the sound. There is a very simple equation to that phenomenon <

I have two more comments that are relevant to comb filtering:

1) At mid and high frequencies the wavelengths are short enough that each ear hears a different response. Therefore, nulls at one ear are filled, or partially filled, by peaks in the other. So you don't notice the effect as much as with a flanger on a track or mix. With a flanger effect you get the same filtering in both channels.

2) When you move 30 cm (about one foot) closer to one speaker in a nearfield environment, the level from each speaker changes enough to reduce the comb filtering. The speaker you're closer to is now louder, and the other is now softer. So that too reduces the effect.

None of this is to argue with you! You are absolutely correct about the importance of comb filtering - at all frequencies - and a lot of people don't understand how significant this really is. If anyone here cares to learn more about this, I produced a video on my company's web site. Look for Comb Filtering, second in the list here:

www.realtraps.com/videos.htm

--Ethan

[Bob Olhsson]

Panpot stereo is not stereo. Real stereo involves multiple microphones picking up the same source. You very much WILL hear the phase relationships between the mikes at low frequencies. Bell Labs wrote this all up in the 1930s as part of the invention of stereo recording.

The single sub rationalization was invented by hi fi manufacturers at the time stereo was introduced to living rooms. While a single sub can make for a pleasant listening setup, it can also create translation problems when used as a mix tool. The film folks learned this lesson the hard way during the 1970s. And yes, a pair of full range speakers is more challenging room design-wise. There's no free lunch.

[seriousfun]

Originally Posted by Bob Olhsson

Panpot stereo is not stereo. ...

That's for sure. The Phantom is the problem. I agree that a mono sound will sound different when it is sent equally to two speakers than if it is played with one speaker, whether it is 40, 400, or 4000 Hz.

Originally Posted by Bob Olhsson

... Bell Labs wrote this all up in the 1930s as part of the invention of stereo recording.
.

I don't think Arthur C. Keller et. al had full range acquisition, delivery, or (possibly)measurement gear - they were, of course, working with 1930s radio and record media in mind.

Originally Posted by Bob Olhsson

The single sub rationalization was invented by hi fi manufacturers at the time stereo was introduced to living rooms.

Well, twenty years later...Ken Kreisel claims the distinction. At the time, the best loudspeakers (Quad/whatever) had low-frequency response limitations, and they could either re-invent the wheel or add a dedicated bass monitor to extend the response of the monitor system - I don't think that for the critical listeners, whether in a studio or home, the difference between one or two subwoofers would have broken the piggy bank.

[weedmaker]

Originally Posted by Bob Olhsson

While a single sub can make for a pleasant listening setup, it can also create translation problems when used as a mix tool.

I've been trying to say this in all my previous posts That's it ...

Cheers

[Bob Olhsson]

Originally Posted by seriousfun

..I don't think Arthur C. Keller et. al had full range acquisition, delivery, or (possibly)measurement gear - they were, of course, working with 1930s radio and record media in mind.

Well, twenty years later...Ken Kreisel claims the distinction.

They were doing basic research into hearing. I was told about this by Jim Johnston who worked for Bell Labs and I recall also learning it in a music psychology class I took at Michigan State around 1964 that was taught from Bell Labs literature. While high frequencies were a challenge, low frequencies were not at all a challenge to acquire and transmit. Obviously there was no way to record broadcast quality sound at the time.

The first summed mono system to be marketed I'm aware of was a satellite speaker and crossover made by Electro-Voice for their top of the line Patrician system in the late 1950s. It was developed because most people were not about to put a second Patrician with its 30" woofer in their living room. The first "subwoofer" intended for Quads was marketed in the early '70s by an obscure manufacturer I can't remember. Ken Kreisel may have been involved but it definitely was not M&K. I think Dahlquest made the first reasonably priced one.

[seriousfun]

Originally Posted by Bob Olhsson

... I recall also learning it in a music psychology class I took at Michigan State around 1964 that was taught from Bell Labs literature. ...

Sounds like the same sources we used in Acoustics Science courses at Berklee about ten years later. As a refreser for me, I found a couple of great resources including http://history.acusd.edu/gen/recording/bell-labs.html.

Originally Posted by Bob Olhsson

... While high frequencies were a challenge, low frequencies were not at all a challenge to acquire and transmit. ...

I think it took a while for speaker and amplifier design to progress to the point where full-range (20 Hz and up) reproduction was practical, in large or small spaces. Recording technology, too. Microphone design probably led the way, from both practical and scientific deveopments.

It's Ken Kreisel's claim, not mine, but he says that 1973 is the year of his first subwoofer, added to Quads for the mix of Pretzel Logic, with commercial units made starting then (sold at Jonas Miller's store) and a powered sub in'77.

I still submit that electrical summing of sub-80 Hz can be more reliable and predictable across a wide variety of small-room environments than acoustic summing. They both need a lot of work to implement properly and from my experience a good, translatable mix can be made with both. The very existence of the OP's question confirms the fact that the art and science here is still a work in progress.

[Anderson]

Ethan

I completely agree with you... We would need a whole book to explain all the factors involved in the hearing process.

Anyway, I will try and run a simulation in our acoustic modelisation program and I will post the "theoritical" results for 1 and 2 subs in an average CR, one auralization (HRTF style) .wav sequence and one simple stereo .wav sequence . It will remain rather abstract (it´s a mathematical model in a simplified room), but will give a good idea of what´s happening in the room. Give me week or two and it will be done! I think it will be rather useful and clarify things a little bit...

Cheers you all slutz!